Most Powerful Women: The list about the list!

We’ve spent the last three months slicing and dicing the accomplishments and career histories of the most powerful women in business — far too many facts and figures to fit into our Most Powerful Women package in the magazine. Here are 10 intriguing facts that we couldn’t find space for in print:

Youngest woman to ever appear on the list: Marissa Mayer, VP of Search and User Experience at Google . At 33 years old, she lands in the No. 50 spot. Before Mayer, the youngest MPWoman ever was Sallie Krawcheck, age 37 in 2002 when she was CEO of Sanford C. Bernstein and debuted at No. 42.

Highest-profile dropoff: Krawcheck, who last week quit her CEO post at Citigroup , where she was chairman and CEO of Global Wealth Management.

Highest-ranking returnee: Safra Catz, co-president of Oracle at No. 16. Catz last appeared in 2005, at No. 49. She has impressively overseen 40-plus acquisitions and earned her way back to a top spot.

Highest-ranking newcomer: Susan Chambers, EVP of the Global People Division at Wal-Mart . Wal-Mart is not only the largest company in the world, it also employs the largest private workforce (over two million!), earning Chambers her spot at No. 25.

Non-CEOs in the top 10: Susan Arnold, No. 7, president of global business units at Procter & Gamble ; Oprah Winfrey, No. 8, chairman of her Harpo Inc. multimedia empire; and Ursula Burns, No. 10, president of Xerox . Burns will likely become CEO of Xerox next year, with Anne Mulcahy staying on as chairman.

Biggest leap at the top: Ellen Kullman, up from No. 25 to No. 15. Last week, she was named president and CEO designate at DuPont . Other major jumps: Heidi Miller, who heads J.P. Morgan Chase’s treasury and securities services unit, from No. 27 to 17, and TJX CEO Carol Meyrowitz, from No. 31 to 19. Her low-price retail chains are winning over shoppers in this sagging economy.

Only MPWoman who doesn’t run a major business or direct the strategy of a corporation: securities analyst Meredith Whitney (No. 35). Oppenheimer & Co.’s hugely influential market mover made the August 18 cover of Fortune for her prescient predictions of plummeting bank stocks.

One woman worth watching, still: Erin Callan, whom we identified as a 2007 “woman to watch,” lost the CFO job at Lehman Brothers in June and found refuge at Credit Suisse , where she now heads the firm’s global hedge fund business. Callan didn’t make our list this year, but she certainly knows power, as she demonstrates in her first interview since leaving Lehman. Read Katie Benner’s exclusive Q&A. – Jessica Shambora